I apologize for the question in advance.

What is the maximum amount of knockback damage
that can be dealt to a single character when adjacent to blocking terrain, such as a wall or a Barrier?

Does a character only receive 1 knockback damage for hitting a wall, despite being "sandwiched" between a wall and an opposing character who deals damage, regardless of the amount of damage dealt, or does the character receive the dealt damage plus an equal amount of damage for being hit against the wall if already adjacent to it?

I humbly ask for your advice.

...and this is after damage-reducing powers have taken effect...

A character will only be dealt 1 click of damage for being knockedback into blocking terrain.

Here is an example:

Attacker A deals 4 damage to Target B on a roll of doubles. B has Toughness and reduces the damage to 3 damage taken. B is clicked 3 times and is knockedback. B hits the wall which is right behind it (so B didn't really physically moved) and is dealt 1 more click of damage. Because B still has Toughness (even after being clicked 3 times)...the Toughness absorbs that damage and B take 0 damage. (If B did not have a damage reducing power -- or CR -- B would have taken 1 click of damage from the knockback.

The way I ahve always undertood it to mean is that it adds one to the damage dealt. Therefore, if a character with Toughness is dealt 3 damage with knockback, he will take a total of 4 for hitting the wall. Toughness wil reduce it by one making the figure take 3 clicks of damage.

See my post above.

Thanks, all! Somehow, although I have been playing since "Day One," I recently became a bit "disoriented" regarding KB damage. Ahem. One more sign that you're getting older...